Definition of the N0 Neck

Clinical staging of the neck consists of physical examination and includes the results of imaging studies.6 Computed tomography (CT) and magnetic resonance imaging (MRI) are commonly employed to evaluate the neck and can be helpful in patients whose necks are difficult to examine by palpation. The radiographic criteria that designate a lymph node as suspicious for metastases include size > 1.0-1.5 cm, spherical shape, evidence of necrosis or soft tissue invasion, and groups of three or more nodes.7,8

Studies that have corroborated CT findings and pathologic staging data from N0 patients now question the accuracy of radiographic staging. An estimated 50% of cervical metastases are <5.0 mm.9 Because micrometastases do not meet the size criteria, they are not considered suspicious on CT. Radiographic staging of the submandibular region in particular may be less accurate than physical examination because most (85%) level I metastases are < 1.0 cm.10'11 CT staging of the neck misses at least one-third of occult cervical metastases.12,13 The sensitivity of CT staging is estimated to be 25%, and the specificity 77%.14 Therefore, pathologic staging is the most accurate tool available to assess the status of the cervical lymphatics.

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